Estimations of the maximum spatial resolution space-borne VHF-band SAR for adaptive synthetic aperture techniques

The certain problems of high-resolution low-frequency space-borne SAR are discussed repeatedly. The main problem of the systems is a coherence loss originated by propagation effects. To the utmost these problems are typical for VHF-band SAR. Conventional synthetic aperture techniques are not effective in these cases. Estimation of the maximum spatial resolution of spaceborne VHF-band SAR for conventional synthetic aperture techniques are familiar. According to the estimations potential resolution SAR deteriorate from several meters to tens and hundreds meters due to propagation effects for wavelength more than one meter. Various adaptive methods for space-borne VHF-band SAR data processing have been previously proposed. The approaches are based on various parametrical and non-parametrical autofocusing algorithms. In particular, the present author proposes a non-parametrical autofocusing algorithm based on the use of the non-stationary model of echo-signals SAR. However, so far the estimates of maximum spatial resolution ofthe space-borne VHF-band SAR are not obtained. The author shows an appropriate analysis for a nonparametrical adaptive algorithm of a SAR image reconstruction based on the use of the non-stationary model echo-signals SAR. Advantages exist of the non-parametrical adaptive techniques of SAR processing in comparison with conventional synthetic aperture techniques, at least, for VHF-band